Muffler



ATTORNEY.

E. P. GRAY MUFFLER Filed Oct. 20. 1921 March 1 1927.

Patented Mar. 1, 1927.

UNITED STATES i EMMET P. GRAY, F DETROIT, MICHIGAN.

MUFFLER.

Application filed October 20, 1921.- Serial No. 509,218.

This invention relates to means for reducing the sound of the exhaust ofinternal combustion engines, and its object 1s to provide a series ofchambers through which the exhaust passesand in which it s permitted toexpand and in which the intermittent impulses are merged into a singlecontinuous discharge, this object being obtained with the least amountof back pressure..

In the accompanying drawing, Fig. 1 is a longitudinal section of thisimproved mufller. Fig. 2 is a side elevation there of. Fig. 3 is a viewshowing one of the steps in the construction of the mufiier. Figs. 4 and5 are sections on the lines and 5-5 of Fig. 1. Figs. 6 and'7 arelongitudinal sections similar to Fig. 1 of two modified forms of thismutfller.

Similar reference characters refer to like parts throughout the severalviews.

In' the several views the exhaust is supposed to travel from left toright, although the direction is immaterial in Fig. 6. The

a structure shown in Figs. .1 to 5 inclusive is made up of two tubes,one within the other, the inner tube being shown made up of two parts 1and 2, although it may be made of one piece. The edges 3 of the sheetsof which these tubes are formed are brought together to constituteflanges, and these extend radially from the body of each tube, as shownin Fig. 5. The ends 4, 5, 6 and 7 are flattened and preferablyspot-Welded together, but if a single tube is used, it may be flattenedintermediate its ends, as at 5-6, and spot-welded as stated.

Enclosing this tube is the outer shell 8 also formed by bending a sheetand causing the longitudinal flanges 9 to extend radially. I prefer tomake one flange sufficient- 1 long to provide a flap 10 which may be fdlded around the other flange 9 when the muflier is assembled with theflanges 3 of the inner tube nested between the flanges 9 of the outertube, as shown in Fig. 5.

The inner tube is formed with groups of perforations 12, 13, 14 and 15,the total area of the perforations of each group being greater than thatof the inlet pipe 16. In

order to secure the inlet pipe and the tail pipe 17 in position, I pressthe metal of the ends 18 of the shell around these pipes, as shown inFig. 3, bringin the parts 19 together, then form the note 20 and fold"the shields,

the tube 2, out through the holes 15 into the flap 21 along the line 22to the position shown in Fig. 2, spat-welding at each step.

Within'the shell 8 and filling the space between it and the inner tubes1 are the substantially frusto-conical shields 24 and 25 having flanges25 extending between the nested flanges 3 and 9 of the tubes 1 and 2 andthe shell 8. As the exhaust enters the shell through the pipe 16, itcushions against the shield 24 and flows through the holes 12 into thetube 1, out through the holes 13 into the space between then through theholes 14 into the rearend of the shell and out through the tail pipe 17.The shield 25 again causes a cushioning of the gas and this cushioningaction of the two shields not only helps to resolve the individualimpulses of the exhaust into a continuous stream, but the piled up gasacts as a dampener on the shell itself and prevents the drumming noisewhich is so often noticed in automobiles.

The construction is very inexpensive as it requires only pieces of sheetmetal which can be bent on the simplest kinds of machines usually usedfor thispurpose. The diameter of the outer shell 8 need ordinarily notbe more than twice the diameter of the exhaust pipe, so that thismuffler requires a minimum of space. The tail pipe 17 may be omitted ifdesired. In Fig. 7 I have shown the shell 45 having a tail pipe 26secured in position as before described and a continuous inner tubeformed of the sections 27 and 28 provided with groups of holes 29, 30and 31 respectively. The exhaust enters at the end 32 of the inner tubeand the outer shell is attached thereto in the manner indicated in Fig.2. The inner tube is flattenedbetween its ends at 32 to divide it intothe two sections and a shield 33 is mounted within the shell to cushionthe gases that enter the space within the shell through the holes 29 andcauses these gases to pass through the holes 30 and 31 into the spaceback of this shield from which they escape through the tail pipe 26. Theend 34 of the inner tube is closed. I

In this case again, the inner tube has radial flanges 35, the shield hasflanges 36 and the shell has flanges 37, all of which are nested and thelower edge of one flange 37 is brought up around the nested flan es, as

indicated in Fig. 5, after which these anges are allspot-weldedtogether.

\ In Fig. 6 the shields are omitted and the inner tube is formed in twosections, 40 and 41, provided with holes 42 and 43 respectively. Theends of the shell 44 are fitted around the ends of the inner tube andthe action of the muflier is substantially the same as of-those abovedescribed, excepting that the action of the shields in cushioning thegases is'omitted. The tube and shell are again formed with nestedflanges as shown in Fig. 5. I

The details of construction and the proportions of the parts may all bechanged by those skilled in the art without departing from the spirit ofmy invention as set'forth in the following claims.

-1. In a muflier, the combination of a cylindrical shell having inletand outlet openings in its ends for exhaust gases, a tube within theshell comprising a plurality of independent sections having closed ends,each section being formed with two groups of holes to permit the passageof exhaust gases, and shields mounted in the shell to prevent thepassage of gases longitudinally of the shell, one shield being mountedbetween the two roups of holes of eachi'tube section, the tu e and shellbeing formed with'radial flanges and the tube contacting with the shellat the flanges thereon and the two groups of holes of each tube section,the

tube, shields and shell having nested radial flanges.

3. In a muffier, the combination of a cylindrical shell and a tubetherein of less diameterv than the shell, one end of the tube within theshell being closed, said tube being formed with a series of groups ofholes.

to permit the passage of exhaust gases, the tube being closed betweentwo of the groups of holes, and a shield mounted on the tube between twogroups of holes to prevent the passage of the gases longitudinally ofthe shell at that point, said shield, shell and tube being formed withnested I parallel radial flanges which'are united together, one of theouter flanges of the shell being bent the other flange of the shell.-

EMJSIET P. GRAY.

around the nestedflanges and attached to. i

